Whatever your definition of "heavy" is, you will need to redefine it after hearing the early works of Earth! Earth was the first band to play drone metal; extremely heavy ambient music created by blaring down-tuned guitars, played at the pace of a death march, without any drums or vocals. Earth played this noisy, slow form of doom up until their second album, 'Phase 3: Thrones and Dominions'. After that, the band began to experiment with a lighter, quieter form of Psychedelic Rock. Overall, the band's early works have been extremely influential to the likes of Boris, Sunn O))), and practically every drone metal band out there today.